High-voltage power-up and power-down of an electric vehicle are generally realized in such a manner that a vehicle control unit (VCU) sends power-up and power-down commands to a battery management system (BMS) through a CAN bus of the vehicle. Under a high-speed running condition, when the communication between the VCU and the BMS is abnormal, the BMS is out of control of the VCU, possibly leading to a case of wrongly switching off a main relay of an electric vehicle.
In the prior art, only the VCU can send commands to the BMS through the CAN to control on and off of the main relay of the vehicle. When the vehicle runs at a high speed or under other circumstances that high-voltage power should not be cut off, certain potential safety hazards will be caused in case of wrong operations of the BMS.